I updated my packages Ubuntu 11.10 with Update manager, and got:
"The package information was just updated" and "There are no updates to install".
But I still have the warning from the restart icon, which is highlighted red. Within it
"Restart to complete the updates" is also highlighted in red. I tried sudo apt-get upgrade and got message as:

Basically it is the information on updates of critical things like kernel so that the new updates are activated after a restart. You need to restart you computer thats it.
–
sagarchaliseDec 2 '11 at 5:02

I think Ivan is implying that nothing was upgraded during his check of system packages, but he still got the warning to restart regardless?
–
ScaineDec 2 '11 at 7:15

3 Answers
3

I agree with sagarchalise. Certain upgrades like kernel updates, driver updates and critical system and security updates need your system to restart after install. You just have to restart your computer.